Texas police say a drunk driver ran over a 70-year-old man and drove her car into a Galveston bayou with her 6-month-old son in the back seat.

Four teens fishing nearby jumped into Offatts Bayou to save Latonya Kirven, 30, and her baby on Monday afternoon. At first the teens, Nathan Reyna, Tyler Arcizo, Byron Bledsoe and Matt Guzman, thought Kirven was in the car alone.

"Once the car was tipping, you see the car seat for the baby tip over. My friend was like, 'There is a baby, there is a baby,'" Arcizo told KHOU.

Kirven was arrested and charged with driving while intoxicated with a child in the vehicle and assault with a deadly weapon. She and the baby were not injured.

Matt Grey, 70, sustained a broken neck and is in critical condition, KHOU reported. Grey and Kirven have a child together but it is unclear whether that child is the 6-month-old.

Police said the crash occurred after the couple had an argument.

Driving into the bayou may not have been an accident. Arcizo said Kirven did not want their help.

"I was struggling with her to get the baby from her," Arcizo said. "She wouldn't give him up. She kept pulling him from me and putting him under water."

Arcizo said he got the infant to shore and Kirven began swimming the backstroke, taking off her clothes.

"She was acting crazy. It wasn't normal," Arcizo said. "She's in jail. That's where she needs to be honestly."

Police do not have a motive for the rampage.

Grey’s granddaughter, Jamie Williams, believes Kirven was on drugs.

"Those drugs have got her mind," Williams told the TV station. "If she was herself, she wouldn't have done it. Those drugs have her flipping out like that."